殺青條件與時間對茶葉中抗壞血酸含量之影響

Effect on Blenching Method and Duration on Ascorbic Acid Content of Tea

本研究採用RQ flex測定殺菁方法與時間對茶葉中抗壞血酸含量之影響。以標準品配置之標準液測試默克公司之RQ-flex中抗壞血酸之準確度，40至200 mg／Kg下，其檢量線之迴歸方程式為y=1.0179x-0.6182, R^2 =0.9992, p＜0.0001，為可靠之檢測設備與方法。試驗材料為手採青心大冇茶菁，上午採收者含抗壞血酸2226±58 mg／100g dry leaf下午採收者則為2137±1 mg／100g dry leaf差異顯著。用手採青心大冇秋茶，以蒸菁30、60、90、120、150、180 sec，微波20、40、60、80、100、120 sec及圓桶式炒菁機以外鍋250℃下1、2、3、4、5、6 min殺菁。結果顯示，蒸菁180 sec者殘存之抗壞血酸最高，達1942.1 mg／100g dry leaf，殘存率89.03%，微波殺菁60 sec上之處理與蒸菁180秒者差異不顯著；炒菁1-2min之處理對抗壞血酸含量之保存效果次之。以殺菁效果與抗壞血酸含量兩項因子考量時，在本研究之設備下，綠茶殺菁之條件，在蒸菁是以180 sec.最佳，以微波殺菁需超過60 sec，炒菁則為1-2min。 According to standard curve, ascorbic acid content is high significant correlated to the record of RQ-flex, the regression equation was y=1.0179x-0.6182, R^2=0.9992 P＜0.0001, and suitable for tea ascorbic acid analysis. Ascorbic acid content in tea shoot which harvest in afternoon was significant lower than that harvest in morning. Autumn and hand plucked succulent shoot of 'Chin-Hsin Dapan' tea were blenched with microwave, steam and panning for six duration. Steam blenching for 180 sec. had highest ascorbic content, which had 1942.1 mg/100g dry leaf ascorbic acid, although microwave treated more then 60 sec. were lower, but there were no significant to 180-sec.-steam treatment. One-and two-min panning also had good results, but significant lower then significant lower then 180-sec.-steam and 60-sec. microwave treatments. Under our condition, 180 sec steam, more then 60 sec microwave, and one or two min. panning, were be the suitable blenching condition for ascorbic content of tea leaf.